Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors

Rahman, F., Xu, S., Watson, I.M., Mutha, D.K.B., Oxland, R.K., Johnson, N.P., Banerjee, A. and Wasige, E. (2009) Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors. Applied Physics A: Materials Science and Processing, 94(3), pp. 633-639. (doi:10.1007/s00339-008-4848-9)

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Abstract

We describe experiments investigating the quality of ohmic contacts to both bulk GaN and to III-nitride heterostructures. Titanium-based contacts were investigated to assess the role of intermixing and surface impurities for contact formation to n-type GaN. Direct contact to the two-dimensional electron gas in GaN/AlGaN heterostructures was also studied. These contacts were made by photochemical etching of the samples to expose the heterointerface. It was observed that even in the latter case contact annealing leads to a lower contact resistance by consuming surface contaminants and promoting beneficial interfacial reactions. Various passivation techniques were tried to reduce surface leakage current between contact pads and PECVD-deposited silicon nitride was found to be the best material for this application.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Wasige, Professor Edward and Johnson, Dr Nigel and Banerjee, Mr Abhishek and Rahman, Dr Faiz and Oxland, Dr Richard
Authors: Rahman, F., Xu, S., Watson, I.M., Mutha, D.K.B., Oxland, R.K., Johnson, N.P., Banerjee, A., and Wasige, E.
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Applied Physics A: Materials Science and Processing
ISSN:0947-8396
ISSN (Online):1432-0630
Published Online:15 August 2008

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